Made Matrix be a typedef to either Matrixf or Matrixd. Defaults to Matrixf.
Converted the osgGA::MatrixManipulators and osgProducer::Viewer/OsgCameraGroup
across to using exclusively Matrixd for internal computations and passing betwen
Manipulators, Producer and SceneView. Note, SceneView still uses Matrix internally
so will depend on what is set as the default in include/osg/Matrix.
Added the ability to osgProducer::setDone/getDone(), kept done() as the
method that the viewer main loop uses for detecting the exit condition.
the text implementation to provide better speed, especially by using the
alignement to screen option.
Deprecated the Text::setFontSize(,) method, which is now being replaced
by setFontResolution(,)
Fixed typos in Texture*.cpp.
Removed old deprecated methods from osg headers.
leaving it up to the Viewer to specify the mode (which by default is MultiThreaded).
Added a check for the presence of osgParticle systems so that threading is
disabled in this case.
